Air cooler



J. PRICE AIR COOLER I Filed July 8,

192] 3 Sheets-Sheet. l

Sept. 23 1924. 7 1,509,566

. J. PFUCZE AIR COOLER Filed July 8, 1921 s Sheets-Sheet 2 Z Svwmtoz Z2 24 @5 job attozwew 1,509,566 J. PRICE AIR COOLER Filed July 8, 1921 3 Sheets-Sheet. 5

Sept. 2:5 1924.

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. H Z i\\\\\\\\\\\ n um M101 M Patented Sept. 23, 1924.

UNITED STATES PATENT OFFICE.

JOSEPH PRICE, O'F NEW YORK, N. Y., ASSIGNOR TO THE GBISCOM RUSSELL COMPANY OF NEW YORK, N. Y., A. CORPORATION OF DELAWARE.

AIR COOLER.

Application filed July 8, 1921.

T 0 all wlz am it may concern Be it known that I, JOSEPH PRICE, a citizen of the United States, residing at No. 2550 Briggs Avenue, New York city, in the county of Bronx, State of New York, have invented certain new and useful Improvements in Air Coolers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains, to make and use the same.

'The present invention relates to an apparatus for transferring heat between two fluid mediums, and is particularly applicable as a heater or cooler for air or other medium which approximately obeys the laws of a perfect gas.

Air dryers, ventilators, and the like are widely used at present in industrial operations. In such apparatus it is ordinarily desirable that the air utilized be clean and dry and, since the atmosphere in the proximity of such apparatus is ordinarily moisture laden and full of dust and other impurities, it is common to pass the air through the apparatus in a closed circuit, thus repeatedly utilizing the same air and supplying only enough additional air to compensate for the leakage and various losses occurring in the apparatus. The temperature of the air is changed as it passes through the ventilator or other appaagain passing it to the apparatus.

ratus, and it is necessary that means be provided in the circuit to restore the volume of the gas to its original temperature beflpre or instance, the ventilating systems employed in connection with large electrical generators and motors such as used on electrically propelled ships and in various industrial plants handle enormous volumes of cooling air and, since dust and dirt accumulated in the windings of these machines would be damaging, it is desirable that the ventilating air be passed in a closed circuit with a cooling device placed at some point in the circuit. electrical machinery of this type may be at a temperature of C., anda cooling device'must be provided which is capable of receiving the air at this high temperature and at the high velocity with which it issues and cool it to a materially lower temperature so that it m y be used. over aga n- The ventilating air issuing from- Serial No. 483,355.

Hereto'fore apparatus of this type commonly consisted of tubes for containing the working fluid and a surrounding air passage, the tubes usually extending between the two tube sheets into which they are expanded or. made tight by means of packed ferrules. The transfer of heat by conduction in a gas is slow,and for efficient heating or cooling of such a medium it is necessary that the gas be brought repeatedly into intimate contact with the heat transferring surfaces. Even the heat transfer rate for gas islow and consequently extensive cooling surfaces are required. In order to provide extensive cooling surfaces within a small space it has been proposed to use tubes for the working fluid which are fluted, finned, or otherwise designed to present a large heat transferring surface. Such a tube construction has not proven satisfactory when used with the usual design above described due to the difiiculty of replacing a damaged tube. When finned tubes are employed a single tube cannot be removed by sliding it through the holes in the tube sheets as can be done with straight tubes of ordinary design. To remove a finned tube it is necessary that one tube sheet be com pletely removed from all the tubes if the unit is of the common design above described.

.It is accordingly an object of the invention to provide an apparatus of thistype of small dimensions, having an extensive heat transferring surface, and having heat transferring elements which are inde enden'tly removable, thus simplifying an making less expensive the necessary repair and maintenance work. I

It is a further object of the invention to provide an apparatus of this type adapted to be built in any capacity and which may line -5 of Fig. 4;

Fig. 6 is a view showing the type of tube construction employed; and

Figs. 7 and 8 are detail views showing modified forms of bottom head; and

Figs. 9 and 10 illustrate .a modified form of water head adapted for multi-pass construction.

Referring to the drawings, particularly I to Figs. 1 to 3, 1 indicates the shell of the ap paratus, shown here as a metallic container of rectangular section which may either be cast or made from sheet metal. The shell 1 is rovided at its ends with flanges 2 and 2 w ich maybe cast integrally with the shell or formed by angle irons riveted to theends of the shell. A rectangular inlet 3 for the air and a similar outlet 4 are provided in the narrower sides of the shell.

These are substantially equal in area to they sides of the shell and are provided with flanges 5 for attachment in series with the other members included in the air circuit.

Within the shell there is positioned a plurality' of longitudinal tubes 6 having their lower ends expanded into a tube sheet 7 which fits against the lower flange 2 and serves as a support for the tubes. The upper ends of the tubes are not secured in a tube sheet as are the lower ends but are left unsupported, and individual cap members 8 of inverted U-sha are expanded, screwed or otherwise suitabl y fastened over the free ends of adjacent tubes, thus grouping the entire body of tubes into a number of independent elements each containing a pair of tubes. Each of the members 8 contains a tubular passage executing a 180 turn and serves as means for connecting the two tubes of the elements in series, the fluid passing up one of the tubes and down the other.

The lower or open ends of the tubes open into a head 9, best shown in Figs. 4 and- 5. This head is a metal casting comprising an inlet 10 for admittin the working fluid into apassage 11 exten ing the length of the head, and an outlet 12 through which the fluid is dischar d from a longitudinal passage 13 exten ing the length of the head.

The head is further divided into a pluralit of transversely extending chambers, the a ternate chambers communicating with the passages 11 and 13 respectively. As shown .m Fig. 4, thechambers 1e are in direct communication with passage 11 and the chambers 15 are shown communicating with passage 13. Liquid enters the inlet 10 and passes immediately into pamage 11 and the chambers in communication therewith, from whence it rises through the tubes which open into these chambers. After ascending the length of these tubes the liquid is directed downwardly by means of the U-shaped caps 8 and descends through the tubes into outlet chambers 15. In this construction the li uid passes up and down the length of the s icll once, thus giving a two-pass cooler.

A cooler of a greater number of passes may readily be obtained by merely altering the construction of the water head 9. Such a modified construction is illustrated in Figs. 9 and 10 in which the water head is so constructed as to produce a tenam cooler. The inlet 10 and outlet 12 may located at the same end of the water head orthey ma be positioned as shown at the opposite en 5 of the head. Liquid enters the inlet 10 and is then admitted to the passage 11 and chambers 14. From the chambers 14 the liquid rises in the tubes which open into these chambers and, after traversing the length of the shell, is directed downwardly through the adjacent tubes of the elements by means of the caps 8. The first two transverse rows of tubes discharge into chambers 15, and the last row. opens into a double chamber 31, passage 13 servin to interconnect the various chambers. 'I hus the total quantity of liquid admitted to the cooler passes up and down the height of the shell once and discharges into chamber 31. This portion of the apparatus is in effect a two-pass cooler similar to the two-pass unit above described.

The chamber 31 is double the size of the chambers 14 and 15 and two transverse rows of tubes open into it. The liquid discharged into this chamber is thus free to ascend in the second of these transverse rows of tubes and also to enter the passage 11, from whence it passes into chambers 14' and ascends the tubes which are in communication therewith. The liquid then makes its way downwardly into chambers 15 and a second double chamber 31% When it reaches the chamber 31 the entire quantity of liquid has traversed the length of the shell four times, and the apparatus thus far constitutes a four-pass cooler consistin of two double pass units. As many of t ese double pass units as desired ma be incor orated into a single apparatus, 1: us afi'or ing as many passes as is desirable for any articular in- 'stallation. The apparatus i lustrated in Figs. 9 and 10 is a ten pass cooler comprising five of these units, the last unit discharging its entire flow into passage 13 and from thence to the outlet 12.

Around the periphery of the head there is formed a flange 16 adapted to fit against the tube sheet 7 and form a fluid tight joint. The chamber walls are flush with the face of flange 16 and fit tightly against tube sheet 7. If desired, packing may be proyided between the contacting surfaces to insure fluid tight joints between chambers and to prevent leakage to the outside of the shell. Tubes 6 are arranged in transverse rows in the tube sheet 7 and are positioned, as is shown in Fig. 1, so that one of the two tubes constituting any of the fluid conveying elements communicates with a chamberla and the other with a chamber 15.

The top of the shell is fitted with a removable cover 17 clamped upon flange 2, packing being provided if desired between the contacting surfaces of the flange and cover to form an air tight joint. The removal ofthe cover 17 gives ready access to all the tubes of the heat transferring element. To, replace a damaged tube it is merely necessary to remove this cover and.

the header, loosen the tubes of the damaged element from the tube sheet 7, and withdraw the damaged element through the top of the shell, a new element then being installed. A damaged heating element may thus be replaced without disturbing any of the other heating elements even though finned tubes are used.

Each of the tubes is provided with an external metallic rib or fin 18, as best shown in Fig. 6. This rib is preferably in the form of a spiral extending substantially the entire length of the tube and may be formed integrally with the tube or may be made of sheet metal and attached in any suitable manner. If desired, a series of concentric ribs positioned one above the other may be employed instead of a single spiral rib. Heat is readily conducted from the fluid without the tube through the rib 18 into the tube shell and thence to the cooling fluid flowing within the tube; or vice versa. Thus a the heat transferring surface is creased and more completely istributed throughout the area of the air assage. Furthermore, especially with the spiral rib, a greater agitation is produced in the pass ing stream and the entire volume of air is thus brought more directly into contact with the heat transferring surfaces.

The air cooler is connected directly in a closed circuit with the apparatus to be cooled by the air, the air conduit being of an area substantially equal to the openings 3 and 4; in the cooler walls. An air stream of large volume enters the cooler at the inlet 3, passes through the apparatus in a direction transgreatly in- ;verse to the cooling tubes, and issues at the outlet 4. Working fluid is admitted at the inlet 10 to passag 11, from whence it flows into and fills all of the chambers 14. From these chambers '14 the fluid is forcedinto the communicating tubes and flows through them to the upper-end of the shell, is reversed in flowing through the cap members 8, and returns-to the lower end of the shell,

as indicated by the arrows on Fig. 1. The discharge from the tubes is received in the chambers 15, from whence it is conveyed into passage 13 and from thence discharged at the outlet 12.

In Fig.7 there is shown a modified form ofhead or chamber for the working fiuid. The tube sheet 7 supports the tubes and rests against flange 2 in the manner already de scribed. Two open rectangular rims 18 and 19 of channel cross-section are arranged around the periphery of the shell, a second tube sheet 20 being inserted between them, thus forming two separate chambers,an inlet chamber 21 and an outlet chamber 22, the latter being closed by a removable plate 2st clamped to the lower flan 'e of rim 19. One of the tubes of each fluid containing element opens into chamber 21 and the other is connected by means of'pipes 23 to the out let chamber 22, watertight joints being provided between the chambers. Pipes 23 may be cast integrally with tube sheet 7 or may having one of the tubes of each fluid conveying element of sufficient length to ex;- tend through the chamber 21 and communicate with the chamber 22, water-tight joints being provided at the intersections with the tube sheet.

Fig. 8 shows a further modified form of head for use in installationswhere it is desired to have a multi pass arrangement for the-working fluid. This head COIlSlSlS ofa metallic casing 26 provided with a flange 27 adapted to fit against the tube sheet 7, and a lower flange 28 against which is fastened a bottom cover 24. A horizontal partition 29 is provided, the space below which forms an outlet chamber 22 and the space above which is divided into a plurality of compartments 30 connected in series by means of the fluid conveying elements. Working fluid is admitted to one of the compartments 30 being then forced up onecf the tubes of one row of the fluid conveying elements, through the cap 8, and ac]: through the other tube of the elements mt o the next succeeding chamber 30, which is in communication with the inlet tube of them. To render the body of tubes stable ing my invention possesses 1 l apparatus may that which would 0t erwise and to prevent movement of the elements relative to each other, a metal sheet 32 of area approximately equal to the cross section of the shell is positioned to rest upon the tops of the various elements see Figure 10. Each of the caps 8 of the tube elements is formed with an upwardly extending prong 33 adapted tofit within a. corresponding perforation in the sheet 32. my desired number of these prongs may be threaded to receive a nut 34 for the purpose of holding the metal sheet in firm contact with the'tops of the tube elements. The various elements are thus spaced rigidy from each other and the construction renders the entire bundle of tubes ri id.

1- have found that an apparatus em dygreat flexibility in the matter of design and is readily adapted to meet the conditions of any installation. It is Well recognized in the art that a high velocity of air is necessary for efiicient heat transfer, since conduction through the volume of the air occurs but slowly and the entire volume of air must be brought into intimate contact with the heat transferring surfaces. A high velocity affords a greater agitation of the gas particles and is otherwise conducive to proper heat transfer and-high over all efliciency of the apparatus. Assuming a fixed height of air passage, the width of a heat transferring apparatus of this general type determines, however, the velocit of the air passed through the cooler. T e velocity of the water through the tubes depends upon the number of tubes in each pass.- Consequently in an apparatus of the ordinary type the num-' ber of tubes per pass an amount of water sufiicie-nt to adequately absorb the heat from the air'often fixes the width of the apparatus at a value so great that the air velocity drops far below that which. would make for highest efiiciency. By employing a number of banks of tubes in parallel in each pass the width of the be reduced to any desired imension without decreasing the number of tubes in each pass. As a result, the normal uantity o cooling .water may be passe desirable necessary to convey through the cooler velocity ver reater than .obtained. of design makes it possible much This flexibility I to build an apparatus to meet the requiremerits of any particular installation which will operate at a hi h efliciencv and beof minimum weight am? volume. have found that in some installations it is possible to use a cooler embodying my invention which has a weight only about one half that of a cooler of the ordinary type designed for the same installation, and in which a small num er f pa es y be eific en ly emof sai through the apparatus at the mostnect the individual elements ployed. The reduction in volume and weight of the ap ratus results in a material reduction 0 costs.

While I have illustrated and described my invention as particularly applied to an air cooler, it is to be understood. that my improved apparatus is applicable to any gas heater or cooler with advantage. The apparatus may also be used with the gas as the working fluid. Ifdesired, continuous tubes of an inverted U-shape may be used instead of straight. tubes connected by the cap 8, the ty being prefera 1y, however, due to greater convenience in manufacture. The details of construction may be varied within the full scope of the appended claims.

I claim:

1. An apparatus of the class described having a containing shell, a gas pasage through the shell, and a fluid passage in heat-exchanging relation therewith comthe gas by the number of ele- In an apparatus of the class described havin a containin shell, a passage through the shell, End a fluid pissage in heat-exchanging relation therewith and comprising, a plurality of tubular elements each including a pair of tubes interconnected at one end and open at the other, a head for receiving the open ends of said tubes, said head being provided with transverse passages for connectin individual transverse rows of tubes, an with longitudinal pamages for connecting said transverse passages so as to place transverse rows elementsin parallel with other transverse rows of elements, and inlet and outlet passages for connecting with said longitudinalpassages.

3. An apparatus of the class described having a containing shell, a gas passage through the shell, 9. fluid passage in heatexchanging relation therewith comprising, a plurality of tubular elements, each includ ing a pair of tubes interconnected at one end and open at the other, a head for receiving the open ends of said tubes, said head being provided with passages so c0nnecting the tubes as to divide said elements into a plurality of groups, said groups being connected in series arrangement, and each of said groups comprising a plurality of rows of tube elements and also provided with other passages so arranged as to conof said groups of construction illustrated in parallel whereby the width of the I s" open at the other, andmeans'for connecting.

the'elemen-ts of each of said transverse rows in parallel and'connecting the. elements of different transverse rows in parallel, where by the width of the gas passage is not fixed by the number of elements in parallel, and heat transferring elements of extended area provided on said tubes and lying .in substantial parallelism with the direction of how of the. gas through the apparatus,

whereby the gas is brought repeatedly into intimate contact with the heat transferring surfaces without substantial interference with the movement thereof.

5. In an apparatus of the class described having a containing shell, a gas passage through the shell, and a fluid pasage in heatexchanging relation therewith and comprislng-a plurality of tubular elements each includ ng a pair of tubes interconnected at one end and open at the other, a head for receiving the open ends of said tubes, saidhead being provided with transverse passages for communicating with individual rows of tubes and with longitudinal passages connecting alternate transverse passages to Place alternate rows of said elements in parallel, andinlet and outlet passages connecting with said longitudinal passages.

6. An apparatus of the class described having a containing shell, a gas passage through the shell, and a fluid passage m heat-exchanging relation therewith. comprising a plurality of tubular elements each including a pair of tubes interconnected at one end and open at the other, a head for receiving the open ends of said tubes, said head being provided with transverse passages for placing the individual tubes eonnected therewith in parallel, and longitudinal passages arranged to interconnect the transverse passages in, such manner that alternate transverse rows of said tubular elements are connected in parallel relation, and inlet and outlet passages connecting with said longitudinal passa es.

7. In an apparatus 0 the class described,

the combination of a casing having two opposite sides open throughout substantially their entire area for connection to a as passage, a tube sheet forming a third s1de to said heater, tubes set in said tube sheets and extending across said gas passage, said tubes being arranged in palrs with the free ends of the tubes of each pair connected, a removable wall forming the side of said casing opposite said tube sheet and a header attached to the outer face of said tube sheet said header having partitions lying between the ends of the tubes of each pair and forming inlet and outlet passages therefor, said header also having inlet and outlet manifolds connecting said inlet passages and outlet passages respectively.

8. In an apparatus of the. class described, the combination of a casing having two opposite sides open throughout substantially their entire area for connection to a as passage, a tube sheet forming a third side to said heater, tubes set in said tube sheets and extending across said gas passage, said tubes beingarranged in pairs with the free ends of the tubes of each pair connected, a removable wall forming the side of said casing opposite said tube sheet and a header attached to the outer face of said tube sheet said header having, partitions extending transversely of said gas passage and lying between the ends of the tubes of each pair and forming. inlet and outlet passages therefor, said header also having inlet and outlet manifolds extending longitudinally of said gas passage and connecting said inlet passages and outlet'passages respectively.

9. -An apparatus of the class described havin a containing shell, a gas passage thoug the shell and a fluid assage in heat exchanging relation therewit comprising a plurality of tubular elements, each including a pair of'tubes interconnected at their outer ends, a supporting plate at the outer ends of the said tubular elements, substantially co-extensive with the bank of tubes constituting the fluid passage, said plate having a series of holes. spaced to correspond to the location of the respective tube elements, and a pro'ecting portion at the inter connected end-o each ofsaid'tubular elements adapted to enter the hole corresponding to that element, thereby supporting said elements as a rigid unitary. body and locating each element with respect to the other elements of the apparatus. I In testimony whereof I aflix m signature.

- JOSEP P ICE 

